1. Field of the Invention
The present invention relates to a technical field of a lens barrel and an imaging apparatus, and particularly to a technical field in which a nut member is made of a metal material and part of the area over which a first movable unit moves overlaps with part of the area over which a second movable unit moves, whereby resistance to impact is improved and size reduction is achieved.
2. Description of the Related Art
Any imaging apparatus, such as a video camera and a still camera, includes a lens barrel having an imaging capability. In recent years, a variety of electronic apparatus, such as mobile phones, personal computers, and PDAs (Personal Digital Assistants), have been used in an increasing number of applications, and some of such electronic apparatus include a built-in lens barrel. Therefore, mobile phones, personal computers, PDAs, and other electronic apparatus including such a built-in lens barrel are also used as imaging apparatus for capturing images.
Some of such lens barrels have a configuration in which an outer enclosure houses a fixed lens, such as an objective lens, a movable unit including movable lenses, such as a focus lens and a zoom lens, an imaging device that converts an image light acquired through the fixed lens and the movable lenses into an image signal, and other components.
Some of such lens barrels include two movable units that can be moved by respective driving mechanisms in the optical axis direction (see JP-A-08-95143, for example). Each of the drive mechanisms includes a drive motor and a lead screw rotated by the drive motor.
Each of the movable units includes a lens holder supported by a guide shaft in such a way that the lens holder can slide in the optical axis direction and a nut portion integrally formed with the lens holder and threadably engaging the lead screw. When the drive motor rotates the lead screw, the movable unit is moved in the direction according to the rotational direction of the lead screw (optical axis direction).